#include <stdio.h>
int main(void) 
{
	char num;
	printf("Input a letter:");
	scanf("%c",&num);
	if(num>=97 && num<=122)
	{
		num-=32;
		printf("The uppercase of input is %c",num);
	}
	else if(num>=65 && num<=90)
	{
		num+=32;
		printf("The lowercase of input is %c",num);
	}
	else
	{
		printf("Not a letter!");
	}
return 0;
}



